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The partial electrochemical reduction of carbon dioxide (CO2) using ceramic oxygen generators (COGs) is well known and widely studied. Conventional COGs use yttria-stabilized zirconia (YSZ) electrolytes and operate at temperatures greater than 700 °C. Operating at a lower temperature has the advantage of reducing the mass of the ancillary components such as insulation and heat exchangers (to reduce the COG oxygen output temperature for comfortable inhalation). Moreover, complete reduction of metabolically produced CO2 (into carbon and oxygen) has the potential of reducing oxygen storage weight if the oxygen can be recovered. Recently, the University of Florida developed novel ceramic oxygen generators employing a bilayer electrolyte of gadolinia-doped ceria and erbia-stabilized bismuth oxide (ESB) for NASA's future exploration of Mars.

Two widespread practices in water treatment are, removal of pollutants via adsorption onto activated carbon, and, oxidation of pollutants using a photocatalyst slurry and ultraviolet radiation. The ultimate goal of this research is to combine the adsorptive properties of carbon and the oxidative properties of titanium dioxide (TiO2), and construct a photocatalytically regenerative carbon filter for 100% water recovery. The premise is that the activated carbon, coated with TiO2, will capture the compounds through traditional filtration and adsorption. Once the carbon becomes exhausted, it can be regenerated in-situ by turning on the UV lamps thereby activating the photocatalyst.

The technical feasibility of applying anaerobic digestion for reduction and stabilization of the organic fraction of solid wastes generated during space missions was investigated. This process has the advantages of not requiring oxygen or high temperature and pressure while producing methane, carbon dioxide, nutrients, and compost as valuable products. High-solids leachbed anaerobic digestion employed here involves a solid-phase fermentation with leachate recycle between new and old reactors for inoculation, wetting, and removal of volatile organic acids during startup. After anaerobic conversion is complete, the compost bed may be used for biofiltration and plant growth medium. The nutrient-rich leachate may also be used as a vehicle for nutrient recycle. Physical properties of representative waste feedstocks were determined to evaluate their space requirements and hydraulic leachability in the selected digester design.

Previous work demonstrated that the Photo-Cat® developed by Purifics is capable of reducing the total organic carbon (TOC) concentration of 51 mg/L to below 0.5 ppm using Degussa P25 titanium dioxide (TiO2) as a photocatalyst. The work also showed that ammonium bicarbonate had a detrimental effect on the rate of photocatalytic oxidation, but did not prevent the system from reaching the potable water specification. Nanometer sized Degussa P25 is very popular and quite frequently used as a benchmark of performance in literature, but it may not be the most effective for oxidizing all waste streams. It is critical that each component of the water recovery system be optimized for power consumption and the effectiveness of the photocatalyst plays an important role in accomplishing this.

Finding a manner to effectively filter water to the purest standards is an ongoing battle for various sectors of science. We present a set of experiments that will report the preparation of the photocatalytic component of our composite particle via sol-gel coatings with titanium n-butoxide with subsequent heat treatment at 500°C for three hours in Argon. Our ultimate goal is to create a particle with regenerative capabilities along with a surface enhanced Raman scattering effect. Characterization techniques were performed using SEM-EDS, and XRD.